US3332094A - Life raft - Google Patents

Description

1967 E. R. VORENKAMP 3,332,094

LIFE RAFT Filed May 11, 1965 2 Sheets-Sheet 1 INVENTOR 1?? VJQWKAWP V ATTORNEYS July 25, W? E. Fi. VORENKAMP Z LIFE RAFT Filed May 11, 1965 2 Sheets-Sheet 2 Z5 224 FA W INVENTOR 33627 gf/affwmnp ATTORNEYS United States Patent 3,332,094 LIFE RAFT Egbert Roeloi Vorenkamp, New Orleans, La., assignor to Salerco, Inc., Orleans Parish, La., a corporation of Louisiana Filed May 11, 1965, Ser. No. 454,784

19 Claims. (Cl. 9-11) This invention relates to a novel life raft, and more particularly, to a life raft which is substantially completely flexible.

Heretofore, life-saving rafts are made of rigid or semirigid construction. The prior art rafts generally obtain their buoyancy by the displacement of a volume of water corresponding to the volume enclosed by the outside surfaces of the rafts. That is to say, the prior art rafts would lose all or a substantial portion of their buoyancy if punctured. This can frequently happen around a sinking ship where fire, explosions and/0r debris are present.

Most of the existing life rafts also suffer from the disadvantage of requiring much space for storage purposes, thereby limiting the number of crafts which can be carried aboard a vessel. Even in the case of air inflatable rubber rafts, it is frequently time-consuming to launch the rafts, and difficult to board the rafts after launching because one cannot jump onto such rafts from a ships deck. The wooden life boats have the further disadvantage of being partially inaccessible in an emer gency-roughly one-half of the wooden life boats on a ship may be lost because the sinking ship is listing heavily on one side thereby rendering the life boats stored along the opposite side of the ship unlaunchable.

It is, therefore, an object of the present invention to provide a novel and improved life raft.

It is another object of the invention to provide a life raft which is substantially completely flexible.

It is a further object of the invention to provide a life raft which is compact in storage and yet has a large carrying capacity when launched.

Another object of the invention is to provide a life raft which is high temperature resistant and whose carrying capacity is not affected by punctures.

Still other objects will be apparent from the following description and claims in conjunction with the accompanying drawings, which illustrate different embodiments of the invention and in which:

FIGURE 1 is a plan view partly in section of one embodiment of the life raft of the present invention;

FIGURE 2 is an elevational view in section taken along line 2-2 in FIGURE 1;

FIGURE 3 is a perspective view showing the details of a corner of the life raft of FIGURE 1;

FIGURE 4 is a plan view of another embodiment of the life raft of the present invention;

FIGURE 5 is a side elevation view of the life raft of FIGURE 4; and

FIGURE 6 is a sectional elevation view taken along line 6-6 in FIGURE 4.

The above objects are obtained by making a life raft from a substantially flat sheet of a cellular synthetic material, without any rigid frame or stiffening members. The buoyancy of the raft results from the difference between the densities of the water and that of the cellular synthetic material.. 7

When a flat sheet of buoyant material is placed in rough water, one would expect that part of the waves would go over the sheet and a part go under the sheet. Unexpectedly, I have found that when a raft made of a sheet of flexible material is placed in a wavy sea, the waves would go under the raft and essentially no water would be washed onto the raft. Such a flexible raft would undulate in a vertical direction in wavy waters, and the 3,332,094 Patented July 25, 1957 presence of the flexible raft would calm the waves in much the same way as a layer of oil commonly known as an oil slick would. In this respect, the flexible raft of the present invention is much more stable in rough waters than the conventional rigid or semi-rigid rafts.

Although a flat sheet of a cellular synthetic material will serve well as a life raft, I prefer to cover the flat surfaces of the flat sheet with a network of a webbing material, such as nylon rope. This network of ropes can serve as a rope ladder for departing personnel when the life raft is draped over a side of a sinking ship. After the raft is launched, the network of ropes will serve as handholds for steadying purposes. V The life raft of my invention can be made of any flexible, cellular synthetic materials. I have found flexible, expanded, and plasticized polyvinyl chloride closed-cell plastic sheets to be particularly suitable. Such a sheet of foamed polyvinyl chloride may be obtained, for example, from the U8. Rubber Company under its trade name Ensolite which has a density of 3.5 to 5 lbs./ft. and water absorption of about 1 lb. of water per cubic foot. Such foamed polyvinyl chloride has excellent thermal insulating quality, tensile strength and shock absorbing property. It is also fire resistant. Another example of suitable foamed material is foamed plasticized polyvinyl chloride in which there are 40 parts of dioctyl phthalate to 60 parts of polyvinyl chloride having a density of 4 lbs/cu. ft.

In one embodiment of the present invention, I increase the tensile strength of the foamed polyvinyl chloride by bonding two sheets of the foamed material together with any suitable adhesive, such as glue, and placing a number of webs or strips of a flexible material having high tensile strength thereinbetween. For this purpose, I prefer to use a number of rubber impregnated nylon webs or straps which, of course, are flexible. The embedded nylon webs can be made to extend beyond the perimeter of the sheets of foamed polyvinyl chloride and be used to secure the network of ropes on both surfaces of the raft in place. Alternatively, the network of ropes may be secured directly, to the raft by threading through eyelets or grommets located at the perimeter of the raft.

In the above discussion, it should be understood that the network of rope covering the outside surfaces of the raft is in addition to and separate from the embedded webs, although they may be made of essentially the same material.

In another embodiment of my invention, a single layer of foamed and plasticized polyvinyl chloride is completely enclosed in a synthetic sheeting material. I prefer to use, as the synthetic sheeting material, a synthetic rubber impregnated nylon cloth which is impermeable to water. The synthetic rubber is preferably one having high tensile strength, tough and high temperature resistant. A suitable synthetic rubber for impregnating the nylon cloth is a butadiene-acrylonitrile polymer containing carbon black which has high tensile strength and can withstand extreme cold and high heat. An example of such buta diene-acrylonitrile polymer is Herecrol, sold by the Heresite & Chemical Co. The layer of foamed polyvinyl chloride may be encased in the nylon cloth impregnated with the butadiene-acrylonitrile rubber as follows:

Cover each of the flat surfaces of the layer of polyvinyl chloride with a sheet of the impregnated nylon cloth. The sheets should have slightly larger areas than a the layer so as to provide a margin for gluing the sheets together. The sheets may be glued together at the margins by the use of uncured butadiene-acrylonitn'le polymer and then curing the polymer to convert the sheets into a sealed bag. The layer of encased polyvinyl chloride may also be bonded to the inside surfaces of the sheets by gluing with the same uncured butadiene-acrylonitrile polymer.

In the case of the last-mentioned embodiment, the sheets of butadiene-acrylonitrile can be made to extend substantially beyond the periphery of the layer of polyvinyl chloride in at least one direction. This excess sheeting material may be rolled and secured to a side of the raft when not in use. When unrolled, this excess sheeting material from two opposite sides of the raft can be secured together to form a semi-enclosed, arched or straight sided tent-like space by using several wooden, metal or plastic laths (which can be stored in the rolled excess sheeting material, for example) as support. Because the butadieneacrylonitrile polymer is high temperature-resistant, the excess sheeting material can serve as a fire wall when there is burning oil on the sea after a shipwreck.

In any of the embodiments, a grab line may be formed by securing a rope around and slightly beyond the periphery of the raft. This grab line can be secured, for example, to the ends of the embedded webs. The purpose of the grab line is, of course, to allow swimmers to hold onto the raft before being rescued.

The life raft of the present invention can be launched by simply dropping the same into the water. No matter which side of the raft is turned up, the raft will be ready for use, an advantage not found in other life rafts or boats.

Since the life raft of the present invention is made of flexible and resilient material having excellent shockabsorbing properties, after the raft is thrown overboard, the persons leaving a sinking ship may get on the raft by simply jumping onto it.

A number of harness clips may be attached to the grab line for lashing several life rafts together thereby forming a floating island. Aside from possible increased stability due to increased size, the floating island will also keep the survivors together for easier rescue. The rescue operation is further assisted by the fact that a life raft according to the present invention sits low on the water and so is not subjected to as much drifting as conventional rafts.

When the rafts of the present invention are not in use, they can be easily stored by rolling into cylindrical form. Because the cellular synthetic materials used to make the rafts are usually good insulating materials, the rafts, with or without a slight modification in their construction, can be used as the insulating material on the carrying vessel. Thus, parallel and flexible steel strips may be substituted for the webs embedded in the polyvinyl chloride layer. These rafts with embedded flexible steel strips can be arched across the ceiling of an airplane, for example, and serve as the insulating material until an accident occurs.

The parallel and flexible steel strips embedded in the plasticized polyvinyl chloride layer will impart great strength to the life raft without substantially affecting its flexibility. Such a raft can be used for transporting heavy equipment and be towed by fitting the steel strips with clips or hooks. A propelling device, such as a marine engine, can be mounted on such a raft. The mounting of a propeller type motor, for example, can be accomplished by cutting a rectangular slot in the raft near the leading edge of the raft, and mounting a supporting frame for the motor (made of wooden beams or metallic bars) around the slot.

The steel strip-reinforced raft can also be used as a floating platform for transferring people and equipment between a boat and a drilling platform located in the open sea. One of the problems of transferring people and equipment to and from a platform (such as one of the so-called Texas Towers) is the fact that the waves tend to smash a small boat against the frame of the platform and frequently people are caught in between and injured. When the raft is used as a platform, a small boat can run onto the raft and a part of the boat would be 4 above the raft. In this way, the boat would be flexibly grounded on the raft and personnel can jump from the boat onto the raft or vice versa. Because the raft is fiexible and resilient, even if a person is caught between the raft and a rigid frame, the resulting injury, if any, would be minor.

In FIGURE 1, a life raft 11 is shown which is made of a substantially flat sheet of a flexible and cellular polyvinyl chloride. A network of nylon ropes 12 covers the life raft. The ropes 12 are knotted at intersections 13 to keep them in place. The ropes 12 are attached to the internal network of webs 14 which extend beyond the edges of the raft (more clearly shown in FIGURE 3). A grab line 15, which is also made of nylon rope, is attached to the ends of the webs 14 and surrounds the life raft 11 circumferentially. Attached to the grab line 15 are a number of harness clips 16 which may be used to lash several life rafts together.

In FIGURE 2, the life raft '11 is shown to be made of two layers of foamed and plasticized polyvinyl chloride 17. Sandwiched between the two layers of polyvinyl chloride are the webs 14. The nylon webs 14 are somewhat longer than the life raft and the ends of each web are exposed. There are two grommets or eyelets 18 and 19 located at each of the exposed ends of webs 14. Grommets 19 are used for threading the ropes 12 and grommets 18 are used for threading the gra-b line 15.

In FIGURE 3, a corner of the life raft of FIGURE 1 is shown in detail. A suitable harness clip 16 is also shown. A cementing material 27 is shown between the two layers of foamed polyvinyl chloride.

In FIGURE 4, another embodiment of the present invention is shown as life raft 20. In this embodiment a single sheet of foamed and plasticized polyvinyl chloride 21 is covered with a high temperature resistant sheeting material 22. The sheeting material 22 is made larger than the raft and the excess on one side is rolled into a roll 23 and secured to that side of the raft by tying strings 24. The excess on the other side is normally rolled and tied up, too, but is shown stretched out. This embodiment of the raft also has a network of ropes 25 covering the surfaces of the raft. Ropes 25, in contrast to ropes 12 of FIGURE 1, are attached to the life raft through grommets 26 located at the edges of sheeting material 22.

In FIGURE 5, the life raft of FIGURE 4 is shown in an elevation view, with the right end of the excess sheeting material 22 being shown in solid line in a stretched out position and in dash line in an upright position for use as a fire wall or weather shield. Flexible wooden laths or metal or plastic strips (not shown) may be stored in roll 23 or under and over ropes 25 without reducing the flexibility of the raft significantly for use in making an arched or straight sided, one-ended tent like structure. The strips would be used to hold the side excesses upright and they may be tied at their apex juncture. The lower end of the strips may rest against the corners between the bottom and side excesses.

The construction of the life raft of FIGURE 4 is shown in detail in FIGURE 6. The flexible and foamed sheet of polyvinyl chloride 21 is shown cemented to the high temperature resistant sheeting material 22.

The invention will now be more particularly described by the following examples:

Example 1 A life raft having a surface area 9' x 14 was made with foamed and plasticized polyvinyl chloride 4" thick. This raft was covered with a sheeting material on both sides. The sheeting material is essentially a nylon cloth impregnated with butadiene-acrylonitrile synthetic rubber coating. Two sheets of the sheeting material were used, each about 20' x 16 in size. The layer of foamed polyvinyl chloride was placed between the two sheets with the 14' edge of the polyvinyl chloride layer parallel to the 16' edge of the sheeting material. In this fashion, about 6 of excess sheeting material appear on each side of the life raft. The outside surfaces of the raft were covered with a network of nylon ropes. This raft was found to have a buoyancy of about 1200 lbs., that is to say, it will support a load of about 1200 lbs. without sinking.

Example 2 A life raft was made by cementing two layers of foamed polyvinyl chloride together. Each of said layers is 20' x 14' in area and 2" thick. Sandwiched between the two layers is a network of nylon webs in an arrangement substantially as shown in FIGURE 1. The outside surfaces of this raft were coated with a coating of butadiene-acrylonitrile synthetic rubber. A network of nylon ropes covered the outside surfaces of this raft, these ropes are secured in position by knotting at intersections and attached to the ends of the webs through eyelets. A grab line made of nylon rope was attached circumferentially around the raft at the ends of the webs.

This life raft was found to be extremely stable in open waters. The raft undulated 'with the waves and substantially no water was thrown onto the raft by the waves. Furthermore, the raft has a dampening effect on the waves similar to that of an oil slick. Thus, when the waves have passed the life raft, their magnitude is reduced and relatively calmer waves followed the raft. This raft was found to be capable of supporting about 5300 lbs.

The invention has been described with reference to the preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit andscope of the invention as defined by the following claims.

What is claimed is: 1. A life raft comprising: a continuous and substantially completely flexible planar layer made from a cellular synthetic material having a density of between about 3.5 to 5 pounds per ft.

and a network of ropes covering all surfaces of said planar layer, said ropes being attached to said planar layer at the periphery thereof. 2. A life raft comprising: a continuous and substantially completely flexible planar layer made from a cellular synthetic material having a density of between about 3.5 to 5 pounds per ft.

a waterproof and high temperature-resistant synthetic sheeting material completely encasing said planar layer, and

a network of ropes covering all outside surfaces of said sheeting material,

said ropes being attached to said sheeting material at the periphery thereof.

3. -A life raft comprising:

a continuous and substantially completely flexible planar layer comprising:

two sheets of a cellular synthetic material having a density of between about 3.5 to 5 pounds per ft. bonded together and having a plurality of webbings embedded thereinbetween, and

a network of ropes covering all surfaces of said planar layer, said ropes being attached to said planar layer at the periphery thereof.

all. A life raft comprising:

a continuous and substantially completely flexible planar layer comprising:

two sheets of a cellular synthetic material having a density of between about 3.5 to 5 pounds per ft. bonded together and having a plurality of webbings n embedded thereinbetween, said planar layer having a waterproof and high temperature-resistant synthetic material coated thereon,

and a network of ropes covering all surfaces of said coated planar layer, said ropes being attached to said coated planar layer at the periphery thereof.

5. A life raft comprising:

a continuous and substantially completely flexible planar layer comprising:

two sheets of a cellular synthetic material having a density of between about 3.5 to 5 pounds per ft. bonded together and having a plurality of webbings embedded thereinbetween,

a waterproof and high temperature-resistant, synthetic sheeting material completely encasing said planar layer, and

a network of ropes covering all outside surfaces of said sheeting material, said ropes being attached to said sheeting material at the periphery thereof.

6. A life raft comprising:

a continuous and substantially completely flexible planar layer comprising:

two sheets of an expanded and plasticized polyvinyl chloride cellular plastic having a density of between about 3.5 to 5 pounds per ft. bonded together and having a plurality of rubber-impregnated nylon webbings embedded between said two sheets, said embedded webbings extending beyond said two sheets,

a coating of a waterproof and high temperature-resistant synthetic rubber material completely covering the outside surfaces of said planar layer,

and a net-work of rubber-impregnated nylon ropes covering all outside surfaces of said coated planar layer, said ropes being attached to said embedded nylon webbing at a point beyond the perimeter of said coated planar layer.

7. A life raft according to claim 6 further comprising a nylon rope attached to the ends of said embedded nylon webbings thereby forming a grab line circumferentially around said life raft.

' 8. A life raft according to claim 7 further comprising a plurality of harness clips attached to said grab line for lashing a plurality of said rafts together to form a large island.

9. A life raft comprising:

a continuous and substantially completely flexible planar layer made of an expanded and plasticized polyvinyl chloride cellular plastic having a density of between about 3.5 to 5 pounds per ftfi,

a waterproof and high temperature-resistant synthetic sheeting material completely encasing said planar layer,

and a network of rubber-impregnated nylon ropes covering all outside surfaces of said sheeting material, said ropes being attached to said sheeting material at the periphery thereof.

10. A life raft according to claim 9 further comprising a rubber-impregnated nylon rope circumferentially attached to the periphery of said sheeting material thereby forming a grab line.

11. A life raft according to claim 10 further compris ing a plurality of harness clips attached to said grab line for lashing a plurality of said rafts together to form a large island.

12. A life raft according to claim 9 wherein said sheeting material extends substantially beyond said planar layer on at least one side of said planar layer, for use as a shield.

13. A life raft according to claim 9 wherein said sheeting material extends substantially beyond said planar layer on two opposite sides of said planar layer to permit the excess sheeting materials to be formed into a tent.

14. A life raft comprising:

acontinuous and substantially completely flexible planar layer comprising:

two sheets of an expanded and plasticized polyvinyl chloride cellular plastic having a density of between about 3.5 to 5 pounds per ft. bonded together and having a plurality of parallal and flexible metallic strips embedded thereinbetween, said'metallic strips extending beyond said two sheets,

a coating of a waterproof and high temperature-resistant synthetic rubber material completely covering the outside surfaces of said planar layer,

and a network of rubber-impregnated nylon ropes covering all surfaces of said coated planar layer, said ropes being attached to said metallic strips at points beyond the perimeter of said coated planar layer.

15. A life raft according to claim 14 further comprising a rubber-impregnated nylon rope attached to the ends of said metallic strips thereby forming a grab line circumferentially around said life raft.

16. A raft according to claim 15 further comprising a plurality of harness clips attached to said grab line for lashing a plurality of said rafts together to form a large island.

17. A life raft comprising:

a continuous and substantially completely flexible planar layer made of an expanded closed cell cellular plastic material having a density of 3.5 to 5 lbs/ft. and said layer being approximately 2 to 4 inches thick,

and a network of ropes covering all surfaces of said References Cited UNITED STATES PATENTS 1/1858 Taggart 911 11/1953 Hoffman 98 11/1964 Shewmake et al. 9-l1 FOREIGN PATENTS 2/ 1946 Australia. 8/1963 Canada. 8/1955 Great Britain. 2/ 1959 Great Britain.

20 MILTON BUCHLER, Primary Examiner.

T. MAJOR, Assistant Examiner.

Claims (1)

1. A LIFE RAFT COMPRISING: A CONTINUOUS AND SUBSTANTIALLY COMPLETELY FLEXIBLE PLANAR LAYER MADE FROM A CELLULAR SYNTHETIC MATERIAL HAVING A DENSITY OF BETWEEN ABOUT 3.5 TO 5 POUNDS PER FT.**3, AND A NETWORK OF ROPES COVERING ALL SURFACES OF SAID PLANAR LAYER, SAID ROPES BEING ATTACHED TO SAID PLANAR LAYER AT THE PERIPHERY THEREOF.

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